Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
6d66f5cd TH |
2 | * fs/sysfs/file.c - sysfs regular (text) file implementation |
3 | * | |
4 | * Copyright (c) 2001-3 Patrick Mochel | |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007 Tejun Heo <teheo@suse.de> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | * | |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
1da177e4 | 14 | #include <linux/kobject.h> |
815d2d50 | 15 | #include <linux/kallsyms.h> |
c6f87733 | 16 | #include <linux/slab.h> |
93265d13 | 17 | #include <linux/fsnotify.h> |
5f45f1a7 | 18 | #include <linux/namei.h> |
4508a7a7 | 19 | #include <linux/poll.h> |
94bebf4d | 20 | #include <linux/list.h> |
52e8c209 | 21 | #include <linux/mutex.h> |
ae87221d | 22 | #include <linux/limits.h> |
060cc749 | 23 | #include <linux/uaccess.h> |
13c589d5 | 24 | #include <linux/seq_file.h> |
73d97146 | 25 | #include <linux/mm.h> |
1da177e4 LT |
26 | |
27 | #include "sysfs.h" | |
28 | ||
85a4ffad | 29 | /* |
58282d8d | 30 | * There's one sysfs_open_file for each open file and one sysfs_open_dirent |
c75ec764 | 31 | * for each sysfs_dirent with one or more open files. |
85a4ffad | 32 | * |
c75ec764 TH |
33 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is |
34 | * protected by sysfs_open_dirent_lock. | |
35 | * | |
13c589d5 TH |
36 | * filp->private_data points to seq_file whose ->private points to |
37 | * sysfs_open_file. sysfs_open_files are chained at | |
58282d8d | 38 | * sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex. |
85a4ffad | 39 | */ |
d7b37889 | 40 | static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
c75ec764 | 41 | static DEFINE_MUTEX(sysfs_open_file_mutex); |
85a4ffad TH |
42 | |
43 | struct sysfs_open_dirent { | |
44 | atomic_t refcnt; | |
a4e8b912 TH |
45 | atomic_t event; |
46 | wait_queue_head_t poll; | |
58282d8d | 47 | struct list_head files; /* goes through sysfs_open_file.list */ |
85a4ffad TH |
48 | }; |
49 | ||
58282d8d | 50 | struct sysfs_open_file { |
bcafe4ee TH |
51 | struct sysfs_dirent *sd; |
52 | struct file *file; | |
52e8c209 | 53 | struct mutex mutex; |
73107cb3 | 54 | int event; |
85a4ffad | 55 | struct list_head list; |
73d97146 TH |
56 | |
57 | bool mmapped; | |
58 | const struct vm_operations_struct *vm_ops; | |
73107cb3 | 59 | }; |
1da177e4 | 60 | |
f9b9a621 TH |
61 | static bool sysfs_is_bin(struct sysfs_dirent *sd) |
62 | { | |
63 | return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR; | |
64 | } | |
65 | ||
13c589d5 TH |
66 | static struct sysfs_open_file *sysfs_of(struct file *file) |
67 | { | |
68 | return ((struct seq_file *)file->private_data)->private; | |
69 | } | |
70 | ||
375b611e TH |
71 | /* |
72 | * Determine ktype->sysfs_ops for the given sysfs_dirent. This function | |
73 | * must be called while holding an active reference. | |
74 | */ | |
75 | static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) | |
76 | { | |
7c6e2d36 | 77 | struct kobject *kobj = sd->s_parent->priv; |
375b611e | 78 | |
785a162d TH |
79 | if (!sysfs_ignore_lockdep(sd)) |
80 | lockdep_assert_held(sd); | |
375b611e TH |
81 | return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; |
82 | } | |
83 | ||
13c589d5 TH |
84 | /* |
85 | * Reads on sysfs are handled through seq_file, which takes care of hairy | |
86 | * details like buffering and seeking. The following function pipes | |
87 | * sysfs_ops->show() result through seq_file. | |
1da177e4 | 88 | */ |
c2b19daf | 89 | static int sysfs_kf_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 90 | { |
13c589d5 | 91 | struct sysfs_open_file *of = sf->private; |
7c6e2d36 | 92 | struct kobject *kobj = of->sd->s_parent->priv; |
c2b19daf | 93 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
1da177e4 | 94 | ssize_t count; |
c2b19daf | 95 | char *buf; |
1da177e4 | 96 | |
13c589d5 TH |
97 | /* acquire buffer and ensure that it's >= PAGE_SIZE */ |
98 | count = seq_get_buf(sf, &buf); | |
99 | if (count < PAGE_SIZE) { | |
100 | seq_commit(sf, -1); | |
101 | return 0; | |
102 | } | |
1da177e4 | 103 | |
13c589d5 | 104 | /* |
c2b19daf TH |
105 | * Invoke show(). Control may reach here via seq file lseek even |
106 | * if @ops->show() isn't implemented. | |
13c589d5 | 107 | */ |
c2b19daf | 108 | if (ops->show) { |
7c6e2d36 | 109 | count = ops->show(kobj, of->sd->priv, buf); |
c2b19daf TH |
110 | if (count < 0) |
111 | return count; | |
112 | } | |
0ab66088 | 113 | |
8118a859 MX |
114 | /* |
115 | * The code works fine with PAGE_SIZE return but it's likely to | |
116 | * indicate truncated result or overflow in normal use cases. | |
117 | */ | |
815d2d50 AM |
118 | if (count >= (ssize_t)PAGE_SIZE) { |
119 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
120 | (unsigned long)ops->show); | |
121 | /* Try to struggle along */ | |
122 | count = PAGE_SIZE - 1; | |
123 | } | |
13c589d5 TH |
124 | seq_commit(sf, count); |
125 | return 0; | |
1da177e4 LT |
126 | } |
127 | ||
c2b19daf TH |
128 | static ssize_t sysfs_kf_bin_read(struct sysfs_open_file *of, char *buf, |
129 | size_t count, loff_t pos) | |
2f0c6b75 | 130 | { |
7c6e2d36 TH |
131 | struct bin_attribute *battr = of->sd->priv; |
132 | struct kobject *kobj = of->sd->s_parent->priv; | |
c2b19daf | 133 | loff_t size = file_inode(of->file)->i_size; |
2f0c6b75 | 134 | |
c2b19daf | 135 | if (!count) |
2f0c6b75 TH |
136 | return 0; |
137 | ||
138 | if (size) { | |
c2b19daf | 139 | if (pos > size) |
2f0c6b75 | 140 | return 0; |
c2b19daf TH |
141 | if (pos + count > size) |
142 | count = size - pos; | |
2f0c6b75 TH |
143 | } |
144 | ||
c2b19daf TH |
145 | if (!battr->read) |
146 | return -EIO; | |
147 | ||
148 | return battr->read(of->file, kobj, battr, buf, pos, count); | |
149 | } | |
150 | ||
151 | static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) | |
152 | { | |
153 | struct sysfs_open_file *of = sf->private; | |
154 | ||
155 | /* | |
156 | * @of->mutex nests outside active ref and is just to ensure that | |
157 | * the ops aren't called concurrently for the same open file. | |
158 | */ | |
159 | mutex_lock(&of->mutex); | |
160 | if (!sysfs_get_active(of->sd)) | |
161 | return ERR_PTR(-ENODEV); | |
162 | ||
163 | /* | |
164 | * The same behavior and code as single_open(). Returns !NULL if | |
165 | * pos is at the beginning; otherwise, NULL. | |
166 | */ | |
167 | return NULL + !*ppos; | |
168 | } | |
169 | ||
170 | static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) | |
171 | { | |
172 | /* | |
173 | * The same behavior and code as single_open(), always terminate | |
174 | * after the initial read. | |
175 | */ | |
176 | ++*ppos; | |
177 | return NULL; | |
178 | } | |
179 | ||
180 | static void kernfs_seq_stop(struct seq_file *sf, void *v) | |
181 | { | |
182 | struct sysfs_open_file *of = sf->private; | |
183 | ||
184 | sysfs_put_active(of->sd); | |
185 | mutex_unlock(&of->mutex); | |
186 | } | |
187 | ||
188 | static int kernfs_seq_show(struct seq_file *sf, void *v) | |
189 | { | |
190 | struct sysfs_open_file *of = sf->private; | |
191 | ||
192 | of->event = atomic_read(&of->sd->s_attr.open->event); | |
193 | ||
194 | return sysfs_kf_seq_show(sf, v); | |
195 | } | |
196 | ||
197 | static const struct seq_operations kernfs_seq_ops = { | |
198 | .start = kernfs_seq_start, | |
199 | .next = kernfs_seq_next, | |
200 | .stop = kernfs_seq_stop, | |
201 | .show = kernfs_seq_show, | |
202 | }; | |
203 | ||
204 | /* | |
205 | * As reading a bin file can have side-effects, the exact offset and bytes | |
206 | * specified in read(2) call should be passed to the read callback making | |
207 | * it difficult to use seq_file. Implement simplistic custom buffering for | |
208 | * bin files. | |
209 | */ | |
210 | static ssize_t kernfs_file_direct_read(struct sysfs_open_file *of, | |
211 | char __user *user_buf, size_t count, | |
212 | loff_t *ppos) | |
213 | { | |
214 | ssize_t len = min_t(size_t, count, PAGE_SIZE); | |
215 | char *buf; | |
216 | ||
217 | buf = kmalloc(len, GFP_KERNEL); | |
2f0c6b75 TH |
218 | if (!buf) |
219 | return -ENOMEM; | |
220 | ||
c2b19daf TH |
221 | /* |
222 | * @of->mutex nests outside active ref and is just to ensure that | |
223 | * the ops aren't called concurrently for the same open file. | |
224 | */ | |
2f0c6b75 TH |
225 | mutex_lock(&of->mutex); |
226 | if (!sysfs_get_active(of->sd)) { | |
c2b19daf | 227 | len = -ENODEV; |
2f0c6b75 TH |
228 | mutex_unlock(&of->mutex); |
229 | goto out_free; | |
230 | } | |
231 | ||
c2b19daf | 232 | len = sysfs_kf_bin_read(of, buf, len, *ppos); |
2f0c6b75 TH |
233 | |
234 | sysfs_put_active(of->sd); | |
235 | mutex_unlock(&of->mutex); | |
236 | ||
c2b19daf | 237 | if (len < 0) |
2f0c6b75 TH |
238 | goto out_free; |
239 | ||
c2b19daf TH |
240 | if (copy_to_user(user_buf, buf, len)) { |
241 | len = -EFAULT; | |
2f0c6b75 TH |
242 | goto out_free; |
243 | } | |
244 | ||
c2b19daf | 245 | *ppos += len; |
2f0c6b75 TH |
246 | |
247 | out_free: | |
248 | kfree(buf); | |
c2b19daf TH |
249 | return len; |
250 | } | |
251 | ||
252 | /** | |
253 | * kernfs_file_read - kernfs vfs read callback | |
254 | * @file: file pointer | |
255 | * @user_buf: data to write | |
256 | * @count: number of bytes | |
257 | * @ppos: starting offset | |
258 | */ | |
259 | static ssize_t kernfs_file_read(struct file *file, char __user *user_buf, | |
260 | size_t count, loff_t *ppos) | |
261 | { | |
262 | struct sysfs_open_file *of = sysfs_of(file); | |
263 | ||
264 | if (sysfs_is_bin(of->sd)) | |
265 | return kernfs_file_direct_read(of, user_buf, count, ppos); | |
266 | else | |
267 | return seq_read(file, user_buf, count, ppos); | |
2f0c6b75 TH |
268 | } |
269 | ||
50b38ca0 TH |
270 | /* kernfs write callback for regular sysfs files */ |
271 | static ssize_t sysfs_kf_write(struct sysfs_open_file *of, char *buf, | |
272 | size_t count, loff_t pos) | |
1da177e4 | 273 | { |
50b38ca0 | 274 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); |
7c6e2d36 | 275 | struct kobject *kobj = of->sd->s_parent->priv; |
0ab66088 | 276 | |
50b38ca0 TH |
277 | if (!count) |
278 | return 0; | |
0ab66088 | 279 | |
50b38ca0 TH |
280 | return ops->store(kobj, of->sd->priv, buf, count); |
281 | } | |
f9b9a621 | 282 | |
50b38ca0 TH |
283 | /* kernfs write callback for bin sysfs files */ |
284 | static ssize_t sysfs_kf_bin_write(struct sysfs_open_file *of, char *buf, | |
285 | size_t count, loff_t pos) | |
286 | { | |
287 | struct bin_attribute *battr = of->sd->priv; | |
288 | struct kobject *kobj = of->sd->s_parent->priv; | |
289 | loff_t size = file_inode(of->file)->i_size; | |
f9b9a621 | 290 | |
50b38ca0 TH |
291 | if (size) { |
292 | if (size <= pos) | |
293 | return 0; | |
294 | count = min_t(ssize_t, count, size - pos); | |
f9b9a621 | 295 | } |
50b38ca0 TH |
296 | if (!count) |
297 | return 0; | |
0ab66088 | 298 | |
50b38ca0 TH |
299 | if (!battr->write) |
300 | return -EIO; | |
1da177e4 | 301 | |
50b38ca0 | 302 | return battr->write(of->file, kobj, battr, buf, pos, count); |
1da177e4 LT |
303 | } |
304 | ||
1da177e4 | 305 | /** |
50b38ca0 | 306 | * kernfs_file_write - kernfs vfs write callback |
8ef445f0 TH |
307 | * @file: file pointer |
308 | * @user_buf: data to write | |
309 | * @count: number of bytes | |
310 | * @ppos: starting offset | |
311 | * | |
50b38ca0 TH |
312 | * Copy data in from userland and pass it to the matching kernfs write |
313 | * operation. | |
1da177e4 | 314 | * |
8ef445f0 TH |
315 | * There is no easy way for us to know if userspace is only doing a partial |
316 | * write, so we don't support them. We expect the entire buffer to come on | |
317 | * the first write. Hint: if you're writing a value, first read the file, | |
318 | * modify only the the value you're changing, then write entire buffer | |
319 | * back. | |
1da177e4 | 320 | */ |
50b38ca0 TH |
321 | static ssize_t kernfs_file_write(struct file *file, const char __user *user_buf, |
322 | size_t count, loff_t *ppos) | |
1da177e4 | 323 | { |
13c589d5 | 324 | struct sysfs_open_file *of = sysfs_of(file); |
f9b9a621 | 325 | ssize_t len = min_t(size_t, count, PAGE_SIZE); |
8ef445f0 | 326 | char *buf; |
1da177e4 | 327 | |
8ef445f0 TH |
328 | buf = kmalloc(len + 1, GFP_KERNEL); |
329 | if (!buf) | |
330 | return -ENOMEM; | |
331 | ||
332 | if (copy_from_user(buf, user_buf, len)) { | |
333 | len = -EFAULT; | |
334 | goto out_free; | |
335 | } | |
336 | buf[len] = '\0'; /* guarantee string termination */ | |
337 | ||
50b38ca0 TH |
338 | /* |
339 | * @of->mutex nests outside active ref and is just to ensure that | |
340 | * the ops aren't called concurrently for the same open file. | |
341 | */ | |
342 | mutex_lock(&of->mutex); | |
343 | if (!sysfs_get_active(of->sd)) { | |
344 | mutex_unlock(&of->mutex); | |
345 | len = -ENODEV; | |
346 | goto out_free; | |
347 | } | |
348 | ||
349 | if (sysfs_is_bin(of->sd)) | |
350 | len = sysfs_kf_bin_write(of, buf, len, *ppos); | |
351 | else | |
352 | len = sysfs_kf_write(of, buf, len, *ppos); | |
353 | ||
354 | sysfs_put_active(of->sd); | |
355 | mutex_unlock(&of->mutex); | |
356 | ||
1da177e4 LT |
357 | if (len > 0) |
358 | *ppos += len; | |
8ef445f0 TH |
359 | out_free: |
360 | kfree(buf); | |
1da177e4 LT |
361 | return len; |
362 | } | |
363 | ||
73d97146 TH |
364 | static void sysfs_bin_vma_open(struct vm_area_struct *vma) |
365 | { | |
366 | struct file *file = vma->vm_file; | |
367 | struct sysfs_open_file *of = sysfs_of(file); | |
368 | ||
369 | if (!of->vm_ops) | |
370 | return; | |
371 | ||
372 | if (!sysfs_get_active(of->sd)) | |
373 | return; | |
374 | ||
375 | if (of->vm_ops->open) | |
376 | of->vm_ops->open(vma); | |
377 | ||
378 | sysfs_put_active(of->sd); | |
379 | } | |
380 | ||
381 | static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
382 | { | |
383 | struct file *file = vma->vm_file; | |
384 | struct sysfs_open_file *of = sysfs_of(file); | |
385 | int ret; | |
386 | ||
387 | if (!of->vm_ops) | |
388 | return VM_FAULT_SIGBUS; | |
389 | ||
390 | if (!sysfs_get_active(of->sd)) | |
391 | return VM_FAULT_SIGBUS; | |
392 | ||
393 | ret = VM_FAULT_SIGBUS; | |
394 | if (of->vm_ops->fault) | |
395 | ret = of->vm_ops->fault(vma, vmf); | |
396 | ||
397 | sysfs_put_active(of->sd); | |
398 | return ret; | |
399 | } | |
400 | ||
401 | static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma, | |
402 | struct vm_fault *vmf) | |
403 | { | |
404 | struct file *file = vma->vm_file; | |
405 | struct sysfs_open_file *of = sysfs_of(file); | |
406 | int ret; | |
407 | ||
408 | if (!of->vm_ops) | |
409 | return VM_FAULT_SIGBUS; | |
410 | ||
411 | if (!sysfs_get_active(of->sd)) | |
412 | return VM_FAULT_SIGBUS; | |
413 | ||
414 | ret = 0; | |
415 | if (of->vm_ops->page_mkwrite) | |
416 | ret = of->vm_ops->page_mkwrite(vma, vmf); | |
417 | else | |
418 | file_update_time(file); | |
419 | ||
420 | sysfs_put_active(of->sd); | |
421 | return ret; | |
422 | } | |
423 | ||
424 | static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr, | |
425 | void *buf, int len, int write) | |
426 | { | |
427 | struct file *file = vma->vm_file; | |
428 | struct sysfs_open_file *of = sysfs_of(file); | |
429 | int ret; | |
430 | ||
431 | if (!of->vm_ops) | |
432 | return -EINVAL; | |
433 | ||
434 | if (!sysfs_get_active(of->sd)) | |
435 | return -EINVAL; | |
436 | ||
437 | ret = -EINVAL; | |
438 | if (of->vm_ops->access) | |
439 | ret = of->vm_ops->access(vma, addr, buf, len, write); | |
440 | ||
441 | sysfs_put_active(of->sd); | |
442 | return ret; | |
443 | } | |
444 | ||
445 | #ifdef CONFIG_NUMA | |
446 | static int sysfs_bin_set_policy(struct vm_area_struct *vma, | |
447 | struct mempolicy *new) | |
448 | { | |
449 | struct file *file = vma->vm_file; | |
450 | struct sysfs_open_file *of = sysfs_of(file); | |
451 | int ret; | |
452 | ||
453 | if (!of->vm_ops) | |
454 | return 0; | |
455 | ||
456 | if (!sysfs_get_active(of->sd)) | |
457 | return -EINVAL; | |
458 | ||
459 | ret = 0; | |
460 | if (of->vm_ops->set_policy) | |
461 | ret = of->vm_ops->set_policy(vma, new); | |
462 | ||
463 | sysfs_put_active(of->sd); | |
464 | return ret; | |
465 | } | |
466 | ||
467 | static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma, | |
468 | unsigned long addr) | |
469 | { | |
470 | struct file *file = vma->vm_file; | |
471 | struct sysfs_open_file *of = sysfs_of(file); | |
472 | struct mempolicy *pol; | |
473 | ||
474 | if (!of->vm_ops) | |
475 | return vma->vm_policy; | |
476 | ||
477 | if (!sysfs_get_active(of->sd)) | |
478 | return vma->vm_policy; | |
479 | ||
480 | pol = vma->vm_policy; | |
481 | if (of->vm_ops->get_policy) | |
482 | pol = of->vm_ops->get_policy(vma, addr); | |
483 | ||
484 | sysfs_put_active(of->sd); | |
485 | return pol; | |
486 | } | |
487 | ||
488 | static int sysfs_bin_migrate(struct vm_area_struct *vma, const nodemask_t *from, | |
489 | const nodemask_t *to, unsigned long flags) | |
490 | { | |
491 | struct file *file = vma->vm_file; | |
492 | struct sysfs_open_file *of = sysfs_of(file); | |
493 | int ret; | |
494 | ||
495 | if (!of->vm_ops) | |
496 | return 0; | |
497 | ||
498 | if (!sysfs_get_active(of->sd)) | |
499 | return 0; | |
500 | ||
501 | ret = 0; | |
502 | if (of->vm_ops->migrate) | |
503 | ret = of->vm_ops->migrate(vma, from, to, flags); | |
504 | ||
505 | sysfs_put_active(of->sd); | |
506 | return ret; | |
507 | } | |
508 | #endif | |
509 | ||
510 | static const struct vm_operations_struct sysfs_bin_vm_ops = { | |
511 | .open = sysfs_bin_vma_open, | |
512 | .fault = sysfs_bin_fault, | |
513 | .page_mkwrite = sysfs_bin_page_mkwrite, | |
514 | .access = sysfs_bin_access, | |
515 | #ifdef CONFIG_NUMA | |
516 | .set_policy = sysfs_bin_set_policy, | |
517 | .get_policy = sysfs_bin_get_policy, | |
518 | .migrate = sysfs_bin_migrate, | |
519 | #endif | |
520 | }; | |
521 | ||
522 | static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma) | |
523 | { | |
524 | struct sysfs_open_file *of = sysfs_of(file); | |
7c6e2d36 TH |
525 | struct bin_attribute *battr = of->sd->priv; |
526 | struct kobject *kobj = of->sd->s_parent->priv; | |
73d97146 TH |
527 | int rc; |
528 | ||
529 | mutex_lock(&of->mutex); | |
530 | ||
531 | /* need of->sd for battr, its parent for kobj */ | |
532 | rc = -ENODEV; | |
533 | if (!sysfs_get_active(of->sd)) | |
534 | goto out_unlock; | |
535 | ||
73d97146 TH |
536 | if (!battr->mmap) |
537 | goto out_put; | |
538 | ||
539 | rc = battr->mmap(file, kobj, battr, vma); | |
540 | if (rc) | |
541 | goto out_put; | |
542 | ||
543 | /* | |
544 | * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() | |
545 | * to satisfy versions of X which crash if the mmap fails: that | |
546 | * substitutes a new vm_file, and we don't then want bin_vm_ops. | |
547 | */ | |
548 | if (vma->vm_file != file) | |
549 | goto out_put; | |
550 | ||
551 | rc = -EINVAL; | |
552 | if (of->mmapped && of->vm_ops != vma->vm_ops) | |
553 | goto out_put; | |
554 | ||
555 | /* | |
556 | * It is not possible to successfully wrap close. | |
557 | * So error if someone is trying to use close. | |
558 | */ | |
559 | rc = -EINVAL; | |
560 | if (vma->vm_ops && vma->vm_ops->close) | |
561 | goto out_put; | |
562 | ||
563 | rc = 0; | |
564 | of->mmapped = 1; | |
565 | of->vm_ops = vma->vm_ops; | |
566 | vma->vm_ops = &sysfs_bin_vm_ops; | |
567 | out_put: | |
568 | sysfs_put_active(of->sd); | |
569 | out_unlock: | |
570 | mutex_unlock(&of->mutex); | |
571 | ||
572 | return rc; | |
573 | } | |
574 | ||
85a4ffad TH |
575 | /** |
576 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
577 | * @sd: target sysfs_dirent | |
58282d8d | 578 | * @of: sysfs_open_file for this instance of open |
85a4ffad TH |
579 | * |
580 | * If @sd->s_attr.open exists, increment its reference count; | |
58282d8d | 581 | * otherwise, create one. @of is chained to the files list. |
85a4ffad TH |
582 | * |
583 | * LOCKING: | |
584 | * Kernel thread context (may sleep). | |
585 | * | |
586 | * RETURNS: | |
587 | * 0 on success, -errno on failure. | |
588 | */ | |
589 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 590 | struct sysfs_open_file *of) |
85a4ffad TH |
591 | { |
592 | struct sysfs_open_dirent *od, *new_od = NULL; | |
593 | ||
594 | retry: | |
c75ec764 | 595 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 596 | spin_lock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
597 | |
598 | if (!sd->s_attr.open && new_od) { | |
599 | sd->s_attr.open = new_od; | |
600 | new_od = NULL; | |
601 | } | |
602 | ||
603 | od = sd->s_attr.open; | |
604 | if (od) { | |
605 | atomic_inc(&od->refcnt); | |
58282d8d | 606 | list_add_tail(&of->list, &od->files); |
85a4ffad TH |
607 | } |
608 | ||
83db93f4 | 609 | spin_unlock_irq(&sysfs_open_dirent_lock); |
c75ec764 | 610 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
611 | |
612 | if (od) { | |
613 | kfree(new_od); | |
614 | return 0; | |
615 | } | |
616 | ||
617 | /* not there, initialize a new one and retry */ | |
618 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
619 | if (!new_od) | |
620 | return -ENOMEM; | |
621 | ||
622 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
623 | atomic_set(&new_od->event, 1); |
624 | init_waitqueue_head(&new_od->poll); | |
58282d8d | 625 | INIT_LIST_HEAD(&new_od->files); |
85a4ffad TH |
626 | goto retry; |
627 | } | |
628 | ||
629 | /** | |
630 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
631 | * @sd: target sysfs_dirent | |
58282d8d | 632 | * @of: associated sysfs_open_file |
85a4ffad | 633 | * |
58282d8d TH |
634 | * Put @sd->s_attr.open and unlink @of from the files list. If |
635 | * reference count reaches zero, disassociate and free it. | |
85a4ffad TH |
636 | * |
637 | * LOCKING: | |
638 | * None. | |
639 | */ | |
640 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 641 | struct sysfs_open_file *of) |
85a4ffad TH |
642 | { |
643 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
83db93f4 | 644 | unsigned long flags; |
85a4ffad | 645 | |
c75ec764 | 646 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 647 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad | 648 | |
73d97146 TH |
649 | if (of) |
650 | list_del(&of->list); | |
651 | ||
85a4ffad TH |
652 | if (atomic_dec_and_test(&od->refcnt)) |
653 | sd->s_attr.open = NULL; | |
654 | else | |
655 | od = NULL; | |
656 | ||
83db93f4 | 657 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
c75ec764 | 658 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
659 | |
660 | kfree(od); | |
661 | } | |
662 | ||
94bebf4d | 663 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 664 | { |
3e519038 | 665 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
7c6e2d36 | 666 | struct kobject *kobj = attr_sd->s_parent->priv; |
58282d8d | 667 | struct sysfs_open_file *of; |
027a485d | 668 | bool has_read, has_write, has_mmap; |
000f2a4d | 669 | int error = -EACCES; |
1da177e4 | 670 | |
0ab66088 | 671 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 672 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 673 | return -ENODEV; |
1da177e4 | 674 | |
49fe6047 | 675 | if (sysfs_is_bin(attr_sd)) { |
7c6e2d36 | 676 | struct bin_attribute *battr = attr_sd->priv; |
1da177e4 | 677 | |
49fe6047 TH |
678 | has_read = battr->read || battr->mmap; |
679 | has_write = battr->write || battr->mmap; | |
027a485d | 680 | has_mmap = battr->mmap; |
49fe6047 TH |
681 | } else { |
682 | const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); | |
1da177e4 | 683 | |
49fe6047 TH |
684 | /* every kobject with an attribute needs a ktype assigned */ |
685 | if (WARN(!ops, KERN_ERR | |
686 | "missing sysfs attribute operations for kobject: %s\n", | |
687 | kobject_name(kobj))) | |
7b595756 | 688 | goto err_out; |
49fe6047 TH |
689 | |
690 | has_read = ops->show; | |
691 | has_write = ops->store; | |
027a485d | 692 | has_mmap = false; |
1da177e4 LT |
693 | } |
694 | ||
49fe6047 TH |
695 | /* check perms and supported operations */ |
696 | if ((file->f_mode & FMODE_WRITE) && | |
697 | (!(inode->i_mode & S_IWUGO) || !has_write)) | |
698 | goto err_out; | |
699 | ||
700 | if ((file->f_mode & FMODE_READ) && | |
701 | (!(inode->i_mode & S_IRUGO) || !has_read)) | |
702 | goto err_out; | |
703 | ||
13c589d5 | 704 | /* allocate a sysfs_open_file for the file */ |
0ab66088 | 705 | error = -ENOMEM; |
58282d8d TH |
706 | of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
707 | if (!of) | |
7b595756 | 708 | goto err_out; |
1da177e4 | 709 | |
027a485d TH |
710 | /* |
711 | * The following is done to give a different lockdep key to | |
712 | * @of->mutex for files which implement mmap. This is a rather | |
713 | * crude way to avoid false positive lockdep warning around | |
714 | * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and | |
715 | * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under | |
716 | * which mm->mmap_sem nests, while holding @of->mutex. As each | |
717 | * open file has a separate mutex, it's okay as long as those don't | |
718 | * happen on the same file. At this point, we can't easily give | |
719 | * each file a separate locking class. Let's differentiate on | |
720 | * whether the file has mmap or not for now. | |
721 | */ | |
722 | if (has_mmap) | |
723 | mutex_init(&of->mutex); | |
724 | else | |
725 | mutex_init(&of->mutex); | |
726 | ||
bcafe4ee TH |
727 | of->sd = attr_sd; |
728 | of->file = file; | |
13c589d5 TH |
729 | |
730 | /* | |
49fe6047 TH |
731 | * Always instantiate seq_file even if read access doesn't use |
732 | * seq_file or is not requested. This unifies private data access | |
733 | * and readable regular files are the vast majority anyway. | |
13c589d5 | 734 | */ |
49fe6047 | 735 | if (sysfs_is_bin(attr_sd)) |
c2b19daf | 736 | error = seq_open(file, NULL); |
49fe6047 | 737 | else |
c2b19daf | 738 | error = seq_open(file, &kernfs_seq_ops); |
13c589d5 TH |
739 | if (error) |
740 | goto err_free; | |
741 | ||
c2b19daf TH |
742 | ((struct seq_file *)file->private_data)->private = of; |
743 | ||
13c589d5 TH |
744 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ |
745 | if (file->f_mode & FMODE_WRITE) | |
746 | file->f_mode |= FMODE_PWRITE; | |
0ab66088 | 747 | |
85a4ffad | 748 | /* make sure we have open dirent struct */ |
58282d8d | 749 | error = sysfs_get_open_dirent(attr_sd, of); |
85a4ffad | 750 | if (error) |
13c589d5 | 751 | goto err_close; |
85a4ffad | 752 | |
b05f0548 | 753 | /* open succeeded, put active references */ |
e72ceb8c | 754 | sysfs_put_active(attr_sd); |
0ab66088 TH |
755 | return 0; |
756 | ||
13c589d5 | 757 | err_close: |
c2b19daf | 758 | seq_release(inode, file); |
13c589d5 | 759 | err_free: |
58282d8d | 760 | kfree(of); |
13c589d5 | 761 | err_out: |
e72ceb8c | 762 | sysfs_put_active(attr_sd); |
1da177e4 LT |
763 | return error; |
764 | } | |
765 | ||
85a4ffad | 766 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 767 | { |
85a4ffad | 768 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
13c589d5 | 769 | struct sysfs_open_file *of = sysfs_of(filp); |
1da177e4 | 770 | |
58282d8d | 771 | sysfs_put_open_dirent(sd, of); |
c2b19daf | 772 | seq_release(inode, filp); |
58282d8d | 773 | kfree(of); |
50ab1a72 | 774 | |
1da177e4 LT |
775 | return 0; |
776 | } | |
777 | ||
73d97146 TH |
778 | void sysfs_unmap_bin_file(struct sysfs_dirent *sd) |
779 | { | |
780 | struct sysfs_open_dirent *od; | |
781 | struct sysfs_open_file *of; | |
782 | ||
783 | if (!sysfs_is_bin(sd)) | |
784 | return; | |
785 | ||
786 | spin_lock_irq(&sysfs_open_dirent_lock); | |
787 | od = sd->s_attr.open; | |
788 | if (od) | |
789 | atomic_inc(&od->refcnt); | |
790 | spin_unlock_irq(&sysfs_open_dirent_lock); | |
791 | if (!od) | |
792 | return; | |
793 | ||
794 | mutex_lock(&sysfs_open_file_mutex); | |
795 | list_for_each_entry(of, &od->files, list) { | |
796 | struct inode *inode = file_inode(of->file); | |
797 | unmap_mapping_range(inode->i_mapping, 0, 0, 1); | |
798 | } | |
799 | mutex_unlock(&sysfs_open_file_mutex); | |
800 | ||
801 | sysfs_put_open_dirent(sd, NULL); | |
802 | } | |
803 | ||
4508a7a7 N |
804 | /* Sysfs attribute files are pollable. The idea is that you read |
805 | * the content and then you use 'poll' or 'select' to wait for | |
806 | * the content to change. When the content changes (assuming the | |
807 | * manager for the kobject supports notification), poll will | |
808 | * return POLLERR|POLLPRI, and select will return the fd whether | |
809 | * it is waiting for read, write, or exceptions. | |
810 | * Once poll/select indicates that the value has changed, you | |
2424b5dd | 811 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
812 | * Reminder: this only works for attributes which actively support |
813 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 814 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
815 | * an appropriate error code). When in doubt, set a suitable timeout value. |
816 | */ | |
817 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
818 | { | |
13c589d5 | 819 | struct sysfs_open_file *of = sysfs_of(filp); |
0ab66088 | 820 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 821 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
822 | |
823 | /* need parent for the kobj, grab both */ | |
e72ceb8c | 824 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 825 | goto trigger; |
4508a7a7 | 826 | |
a4e8b912 | 827 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 828 | |
e72ceb8c | 829 | sysfs_put_active(attr_sd); |
0ab66088 | 830 | |
58282d8d | 831 | if (of->event != atomic_read(&od->event)) |
0ab66088 | 832 | goto trigger; |
4508a7a7 | 833 | |
1af3557a | 834 | return DEFAULT_POLLMASK; |
0ab66088 TH |
835 | |
836 | trigger: | |
1af3557a | 837 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
838 | } |
839 | ||
f1282c84 NB |
840 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
841 | { | |
842 | struct sysfs_open_dirent *od; | |
83db93f4 | 843 | unsigned long flags; |
f1282c84 | 844 | |
83db93f4 | 845 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 846 | |
fc60bb83 ND |
847 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
848 | od = sd->s_attr.open; | |
849 | if (od) { | |
850 | atomic_inc(&od->event); | |
851 | wake_up_interruptible(&od->poll); | |
852 | } | |
f1282c84 NB |
853 | } |
854 | ||
83db93f4 | 855 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
856 | } |
857 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
858 | ||
8c0e3998 | 859 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 860 | { |
51225039 | 861 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 862 | |
51225039 TH |
863 | mutex_lock(&sysfs_mutex); |
864 | ||
865 | if (sd && dir) | |
cfec0bc8 | 866 | sd = sysfs_find_dirent(sd, dir, NULL); |
51225039 | 867 | if (sd && attr) |
cfec0bc8 | 868 | sd = sysfs_find_dirent(sd, attr, NULL); |
f1282c84 NB |
869 | if (sd) |
870 | sysfs_notify_dirent(sd); | |
51225039 TH |
871 | |
872 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
873 | } |
874 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
875 | ||
4b6f5d20 | 876 | const struct file_operations sysfs_file_operations = { |
c2b19daf | 877 | .read = kernfs_file_read, |
50b38ca0 | 878 | .write = kernfs_file_write, |
044e3bc3 | 879 | .llseek = generic_file_llseek, |
1da177e4 LT |
880 | .open = sysfs_open_file, |
881 | .release = sysfs_release, | |
4508a7a7 | 882 | .poll = sysfs_poll, |
1da177e4 LT |
883 | }; |
884 | ||
f9b9a621 | 885 | const struct file_operations sysfs_bin_operations = { |
c2b19daf | 886 | .read = kernfs_file_read, |
50b38ca0 | 887 | .write = kernfs_file_write, |
f9b9a621 | 888 | .llseek = generic_file_llseek, |
73d97146 | 889 | .mmap = sysfs_bin_mmap, |
49fe6047 TH |
890 | .open = sysfs_open_file, |
891 | .release = sysfs_release, | |
892 | .poll = sysfs_poll, | |
f9b9a621 TH |
893 | }; |
894 | ||
58292cbe TH |
895 | int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
896 | const struct attribute *attr, int type, | |
897 | umode_t amode, const void *ns) | |
1da177e4 | 898 | { |
0f423895 | 899 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 900 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 901 | struct sysfs_dirent *sd; |
23dc2799 | 902 | int rc; |
1da177e4 | 903 | |
3007e997 TH |
904 | sd = sysfs_new_dirent(attr->name, mode, type); |
905 | if (!sd) | |
906 | return -ENOMEM; | |
487505c2 EB |
907 | |
908 | sd->s_ns = ns; | |
7c6e2d36 | 909 | sd->priv = (void *)attr; |
a2db6842 | 910 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 911 | |
d69ac5a0 TH |
912 | sysfs_addrm_start(&acxt); |
913 | rc = sysfs_add_one(&acxt, sd, dir_sd); | |
23dc2799 | 914 | sysfs_addrm_finish(&acxt); |
a26cd722 | 915 | |
23dc2799 | 916 | if (rc) |
967e35dc | 917 | sysfs_put(sd); |
3007e997 | 918 | |
23dc2799 | 919 | return rc; |
1da177e4 LT |
920 | } |
921 | ||
922 | ||
0f423895 JB |
923 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
924 | int type) | |
925 | { | |
58292cbe | 926 | return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL); |
0f423895 JB |
927 | } |
928 | ||
1da177e4 | 929 | /** |
58292cbe TH |
930 | * sysfs_create_file_ns - create an attribute file for an object with custom ns |
931 | * @kobj: object we're creating for | |
932 | * @attr: attribute descriptor | |
933 | * @ns: namespace the new file should belong to | |
1da177e4 | 934 | */ |
58292cbe TH |
935 | int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
936 | const void *ns) | |
1da177e4 | 937 | { |
608e266a | 938 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 939 | |
58292cbe TH |
940 | return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
941 | attr->mode, ns); | |
1da177e4 LT |
942 | |
943 | } | |
58292cbe | 944 | EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
1da177e4 | 945 | |
1c205ae1 AK |
946 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
947 | { | |
948 | int err = 0; | |
949 | int i; | |
950 | ||
951 | for (i = 0; ptr[i] && !err; i++) | |
952 | err = sysfs_create_file(kobj, ptr[i]); | |
953 | if (err) | |
954 | while (--i >= 0) | |
955 | sysfs_remove_file(kobj, ptr[i]); | |
956 | return err; | |
957 | } | |
1b866757 | 958 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 959 | |
dfa87c82 AS |
960 | /** |
961 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
962 | * @kobj: object we're acting for. | |
963 | * @attr: attribute descriptor. | |
964 | * @group: group name. | |
965 | */ | |
966 | int sysfs_add_file_to_group(struct kobject *kobj, | |
967 | const struct attribute *attr, const char *group) | |
968 | { | |
608e266a | 969 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
970 | int error; |
971 | ||
11f24fbd | 972 | if (group) |
388975cc | 973 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
974 | else |
975 | dir_sd = sysfs_get(kobj->sd); | |
976 | ||
608e266a TH |
977 | if (!dir_sd) |
978 | return -ENOENT; | |
979 | ||
980 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
981 | sysfs_put(dir_sd); | |
982 | ||
dfa87c82 AS |
983 | return error; |
984 | } | |
985 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
986 | ||
31e5abe9 KS |
987 | /** |
988 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
989 | * @kobj: object we're acting for. | |
990 | * @attr: attribute descriptor. | |
991 | * @mode: file permissions. | |
992 | * | |
993 | */ | |
49c19400 | 994 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 995 | umode_t mode) |
31e5abe9 | 996 | { |
06fc0d66 | 997 | struct sysfs_dirent *sd; |
bc062b1b | 998 | struct iattr newattrs; |
51225039 TH |
999 | int rc; |
1000 | ||
5d60418e | 1001 | sd = sysfs_get_dirent(kobj->sd, attr->name); |
06fc0d66 | 1002 | if (!sd) |
5d60418e | 1003 | return -ENOENT; |
f88123ea | 1004 | |
06fc0d66 | 1005 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 1006 | newattrs.ia_valid = ATTR_MODE; |
f88123ea | 1007 | |
5d60418e TH |
1008 | rc = kernfs_setattr(sd, &newattrs); |
1009 | ||
1010 | sysfs_put(sd); | |
51225039 | 1011 | return rc; |
31e5abe9 KS |
1012 | } |
1013 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
1014 | ||
1da177e4 | 1015 | /** |
58292cbe TH |
1016 | * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
1017 | * @kobj: object we're acting for | |
1018 | * @attr: attribute descriptor | |
1019 | * @ns: namespace tag of the file to remove | |
1da177e4 | 1020 | * |
58292cbe | 1021 | * Hash the attribute name and namespace tag and kill the victim. |
1da177e4 | 1022 | */ |
58292cbe TH |
1023 | void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
1024 | const void *ns) | |
1da177e4 | 1025 | { |
58292cbe | 1026 | struct sysfs_dirent *dir_sd = kobj->sd; |
487505c2 | 1027 | |
879f40d1 | 1028 | kernfs_remove_by_name_ns(dir_sd, attr->name, ns); |
1da177e4 | 1029 | } |
58292cbe | 1030 | EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
1da177e4 | 1031 | |
1b18dc2b | 1032 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
1033 | { |
1034 | int i; | |
1035 | for (i = 0; ptr[i]; i++) | |
1036 | sysfs_remove_file(kobj, ptr[i]); | |
1037 | } | |
1b866757 | 1038 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 1039 | |
dfa87c82 AS |
1040 | /** |
1041 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
1042 | * @kobj: object we're acting for. | |
1043 | * @attr: attribute descriptor. | |
1044 | * @group: group name. | |
1045 | */ | |
1046 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
1047 | const struct attribute *attr, const char *group) | |
1048 | { | |
608e266a | 1049 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 1050 | |
11f24fbd | 1051 | if (group) |
388975cc | 1052 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
1053 | else |
1054 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 1055 | if (dir_sd) { |
879f40d1 | 1056 | kernfs_remove_by_name(dir_sd, attr->name); |
608e266a | 1057 | sysfs_put(dir_sd); |
dfa87c82 AS |
1058 | } |
1059 | } | |
1060 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
1061 | ||
3124eb16 TH |
1062 | /** |
1063 | * sysfs_create_bin_file - create binary file for object. | |
1064 | * @kobj: object. | |
1065 | * @attr: attribute descriptor. | |
1066 | */ | |
1067 | int sysfs_create_bin_file(struct kobject *kobj, | |
1068 | const struct bin_attribute *attr) | |
1069 | { | |
1070 | BUG_ON(!kobj || !kobj->sd || !attr); | |
1071 | ||
1072 | return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR); | |
1073 | } | |
1074 | EXPORT_SYMBOL_GPL(sysfs_create_bin_file); | |
1075 | ||
1076 | /** | |
1077 | * sysfs_remove_bin_file - remove binary file for object. | |
1078 | * @kobj: object. | |
1079 | * @attr: attribute descriptor. | |
1080 | */ | |
1081 | void sysfs_remove_bin_file(struct kobject *kobj, | |
1082 | const struct bin_attribute *attr) | |
1083 | { | |
879f40d1 | 1084 | kernfs_remove_by_name(kobj->sd, attr->attr.name); |
3124eb16 TH |
1085 | } |
1086 | EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); | |
1087 | ||
d9a9cdfb | 1088 | struct sysfs_schedule_callback_struct { |
66942064 AC |
1089 | struct list_head workq_list; |
1090 | struct kobject *kobj; | |
d9a9cdfb AS |
1091 | void (*func)(void *); |
1092 | void *data; | |
523ded71 | 1093 | struct module *owner; |
d9a9cdfb AS |
1094 | struct work_struct work; |
1095 | }; | |
1096 | ||
d110271e | 1097 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
1098 | static DEFINE_MUTEX(sysfs_workq_mutex); |
1099 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
1100 | static void sysfs_schedule_callback_work(struct work_struct *work) |
1101 | { | |
1102 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
1103 | struct sysfs_schedule_callback_struct, work); | |
1104 | ||
1105 | (ss->func)(ss->data); | |
1106 | kobject_put(ss->kobj); | |
523ded71 | 1107 | module_put(ss->owner); |
66942064 AC |
1108 | mutex_lock(&sysfs_workq_mutex); |
1109 | list_del(&ss->workq_list); | |
1110 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
1111 | kfree(ss); |
1112 | } | |
1113 | ||
1114 | /** | |
1115 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
1116 | * @kobj: object we're acting for. | |
1117 | * @func: callback function to invoke later. | |
1118 | * @data: argument to pass to @func. | |
523ded71 | 1119 | * @owner: module owning the callback code |
d9a9cdfb AS |
1120 | * |
1121 | * sysfs attribute methods must not unregister themselves or their parent | |
1122 | * kobject (which would amount to the same thing). Attempts to do so will | |
1123 | * deadlock, since unregistration is mutually exclusive with driver | |
1124 | * callbacks. | |
1125 | * | |
1126 | * Instead methods can call this routine, which will attempt to allocate | |
1127 | * and schedule a workqueue request to call back @func with @data as its | |
1128 | * argument in the workqueue's process context. @kobj will be pinned | |
1129 | * until @func returns. | |
1130 | * | |
1131 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
1132 | * be allocated, -ENODEV if a reference to @owner isn't available, |
1133 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
1134 | */ |
1135 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 1136 | void *data, struct module *owner) |
d9a9cdfb | 1137 | { |
66942064 | 1138 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 1139 | |
523ded71 AS |
1140 | if (!try_module_get(owner)) |
1141 | return -ENODEV; | |
66942064 AC |
1142 | |
1143 | mutex_lock(&sysfs_workq_mutex); | |
1144 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
1145 | if (ss->kobj == kobj) { | |
d110271e | 1146 | module_put(owner); |
66942064 AC |
1147 | mutex_unlock(&sysfs_workq_mutex); |
1148 | return -EAGAIN; | |
1149 | } | |
1150 | mutex_unlock(&sysfs_workq_mutex); | |
1151 | ||
d110271e | 1152 | if (sysfs_workqueue == NULL) { |
086a377e | 1153 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
1154 | if (sysfs_workqueue == NULL) { |
1155 | module_put(owner); | |
1156 | return -ENOMEM; | |
1157 | } | |
1158 | } | |
1159 | ||
d9a9cdfb | 1160 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
1161 | if (!ss) { |
1162 | module_put(owner); | |
d9a9cdfb | 1163 | return -ENOMEM; |
523ded71 | 1164 | } |
d9a9cdfb AS |
1165 | kobject_get(kobj); |
1166 | ss->kobj = kobj; | |
1167 | ss->func = func; | |
1168 | ss->data = data; | |
523ded71 | 1169 | ss->owner = owner; |
d9a9cdfb | 1170 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
1171 | INIT_LIST_HEAD(&ss->workq_list); |
1172 | mutex_lock(&sysfs_workq_mutex); | |
1173 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
1174 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 1175 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
1176 | return 0; |
1177 | } | |
1178 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |